Antenna device and portable wireless device using the same

Abstract

Disclosed herein is an antenna device that includes a planar coil pattern formed on a substrate and a composite magnetic sheet positioned on an opposite side to the substrate with respect to the planar coil pattern. The composite magnetic sheet comprises soft magnetic metal powder and binder resin. The composite magnetic sheet is supported with a predetermined distance from the planar coil pattern.

What is claimed is: 
     
         1 . An antenna device comprising:
 a planar coil pattern formed on a substrate; and   a composite magnetic sheet positioned on an opposite side to the substrate with respect to the planar coil pattern,   wherein the composite magnetic sheet comprises soft magnetic metal powder and binder resin, and   wherein the composite magnetic sheet is supported with a predetermined distance from the planar coil pattern.   
     
     
         2 . The antenna device as claimed in  claim 1 , further comprising a spacer layer provided between the planar coil pattern and the composite magnetic sheet so as to keep a distance between the planar coil pattern and composite magnetic sheet at the predetermine distance. 
     
     
         3 . The antenna device as claimed in  claim 1 , wherein the predetermined distance is 20 μm or more. 
     
     
         4 . The antenna device as claimed in  claim 1 , wherein the soft magnetic metal powder is insulation-coated. 
     
     
         5 . The antenna device as claimed in  claim 4 , wherein the predetermined distance is 10 μm or more. 
     
     
         6 . The antenna device as claimed in  claim 4 , wherein the soft magnetic metal powder has a flat shape. 
     
     
         7 . The antenna device as claimed in  claim 1 , wherein a metal pattern is disposed on an opposite side to the planar coil pattern with respect to the composite magnetic sheet. 
     
     
         8 . The antenna device as claimed in  claim 7 , wherein the metal pattern is a part of a battery pack. 
     
     
         9 . The antenna device as claimed in  claim 7 , wherein the predetermine distance is equal to or less than a distance between the composite magnetic sheet and metal pattern. 
     
     
         10 . The antenna device as claimed in  claim 1 , wherein the antenna device is used for near field wireless communication where data is transmitted/received at a frequency of 13.56 MHz. 
     
     
         11 . A portable wireless device having an antenna device, wherein the antenna device comprising:
 a planar coil pattern formed on a substrate; and   a composite magnetic sheet positioned on an opposite side to the substrate with respect to the planar coil pattern,   wherein the composite magnetic sheet comprises soft magnetic metal powder and binder resin, and   wherein the composite magnetic sheet is supported with a predetermined distance from the planar coil pattern.   
     
     
         12 . An antenna device comprising:
 a substrate having front and back surfaces opposite to each other, the back surface of the substrate being fixed to a support member;   a coil pattern formed on the front surface of the substrate; and   a magnetic sheet covering the coil pattern with a predetermined distance from the coil pattern so as not to contact the coil pattern.   
     
     
         13 . The antenna device as claimed in  claim 12 , further comprising a spacer provided between the coil pattern and the magnetic sheet. 
     
     
         14 . The antenna device as claimed in  claim 12 , wherein the magnetic sheet is fixed to another support member. 
     
     
         15 . The antenna device as claimed in  claim 14 , wherein the coil pattern faces the magnetic sheet with an intervention of a free space. 
     
     
         16 . The antenna device as claimed in  claim 14 , wherein the predetermine distance is less than a distance between the magnetic sheet and the another support member.